Sherman Hospital's new geothermal system is paying off

Ray Diehl, director of engineering at Advocate Sherman Hospital in Elgin, says the geothermal system is high-maintenance but has yielded savings close to $1 million annually.Laura Stoecker | Staff Photographer

Advocate Sherman Hospital's geothermal system includes 171 manifold rafts, each with a pressure gauge. The system requires a rigorous inspection schedule.Laura Stoecker | Staff Photographer

Advocate Sherman Hospital's geothermal system, which heats and cools the hospital through a 15-acre lake, includes four circulating pumps.Laura Stoecker | Staff Photographer

The 15-acre geothermal lake at Advocate Sherman Hospital in Elgin has more than 150 miles of piping at the bottom of the lake. The hospital opened in 2009.Laura Stoecker | Staff Photographer

Four years after Elgin's Advocate Sherman Hospital opened a state-of-the art facility with a geothermal system to heat and cool the facility, officials say the cost savings have pretty much mirrored estimates.

The hospital is heated and cooled by a 15-acre, 18-foot-deep lake through a massive system of 185 miles of pipes that pull heat from the lake in winter, and discharge it into the lake in summer.

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It's the only geothermal hospital system in Illinois, and the largest in the country, Sherman's director of engineering Ray Diehl said.

Before the hospital opened in December 2009, officials estimated it would save $1 million a year in energy costs. In the first year, the hospital saved $1.29 million compared to energy bills at the old Sherman Hospital near downtown Elgin, he said.

That stems from an 80 percent decrease in natural gas use and a 72 percent decrease in water use, coupled with a 15 percent increase in electric use, he said. Savings have since dropped to $800,000 to $900,000 per year because of lower natural gas and electricity rates.

"We've been pretty much on track from what (engineers) calculated," he said.

The system requires a rigorous inspection schedule and there have been leaks in some of the system's plastic pipes, said Diehl, who supervises a staff of 21 people. "It is a high-maintenance system," he said.

The initial plan called for steel pipes, but the hospital's contractor offered to use some plastic pipes to cut costs, said Warren Lloyd, vice president and principal at Rock Island-based KJWW Engineering Consultants, the engineering firm for the project.

No leaks have affected patients, Diehl said. There are no plastic pipes in patients' rooms, but there are some in corridors and outpatient areas, he said.

"As we get leaks we shut down and repair and replace them."

The most serious leak occurred in February 2012, when a plastic pipe fitting split and dumped massive quantities of the antifreeze methanol, causing $1 million in damage to the medical records department, Diehl said. Insurance covered all but $25,000 of the loss.

The leak happened on a Sunday morning; no employees were present, and no medical records were affected, Diehl said.

"We're still not quite sure what happened," he said. "It lasted almost 1½ years before it broke, so it's very odd."

Geothermal systems are a rarity among hospitals, partly because it's difficult to retrofit a hospital, while it's much easier to do so for a hotel or college dorm, Lloyd said.

"It's a completely different technology to maintain it. Some people are just hesitant to adopt that," he said.

The geothermal system cost about $6 million, including land purchase, Lloyd said. The cost of the hospital complex was about $310 million.

Sherman's lake is naturally fed by runoff and condensation; extra water had to be added only after last year's drought, Diehl said.

A .7-mile walking path often used by hospital staff surrounds the lake, which is stocked with catfish, crappie, bass and more, though no fishing is allowed.

Among the perks of the job is hosting tours about the geothermal system, Diehl said. Visitors range from groups of students from Community Unit District 300 and Elgin Area School District U-46, to engineers and officials from as far off as Bermuda, Kuwait, the Netherlands and South Africa.

"They're just kind of amazed at the size of this system," Diehl said.

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